This data includes the dissolved organic matter (DOM) molecular composition data obtained via Fourier-transform ion cyclotron resonance mass spectrometry and the accompanying metadata (cruise, station number, geographic coordinates, water depth, temperature, salinity and solid-phase extracted dissolved organic carbon concentrations (SPE-DOC)) for multiple oceanographic cruises (HOTS, BATS, SO254, SO245, SO248, ANT 28-II, ANT 28-IV, and 28-V). This data was analyzed in Bercovici et al., 2023 (https://doi.org/10.1029/2023GB007740). DOM composition data for the cruise SO245 was previously published in Osterholz et al., 2021 (https://doi.org/10.1016/j.marchem.2021.103955). In order to maximize comparability among data, we reanalyzed the same set of samples from SO245 on the FT-ICR-MS together with the samples from the other cruises and sites. SPE-DOC concentrations were determined on a Shimadzu TOC-VPCH total organic carbon analyzer. DOM composition was determined on a SolariX XR FT-ICR-MS (Bruker Daltonik GmbH, Bremen, Germany) equipped with a 15 Tesla superconducting magnet and an electrospray ionization source (ESI; Bruker Apollo II ion source). The metadata were compiled from the CTD bottle data of multiple cruises, some of which are available on PANGAEA at the following links: SO248: https://doi.org/10.1594/PANGAEA.864673, SO245: https://doi.org/10.1594/PANGAEA.890394, SO254: https://doi.org/10.1594/PANGAEA.890453.

The authors gratefully acknowledge Aron Stubbins, Natasha McDonald, and John Casey for collection of the HOTS and BATS samples.